I have the following bash script:
!/bin/bash
# script to send simple email
#Wait 5 seconds
#sleep 05
# email subject
SUBJECT="SUBJECT"
# Email To ?
EMAIL="EMAIL"
# Email text/message
MYIP=$(curl http://ipecho.net/plain)
LASTIP=$(head -n 1 /home/ubuntu/myip.txt)
echo "Last IP:" $LASTIP
echo "Current IP:" $MYIP
#Check if IPs are the same
if [[ "$MYIP" == "$LASTIP" ]]; then
echo "IP hasn't changed. Do nothing."
else
sendemail -f $EMAIL -t $EMAIL -u $SUBJECT -m $MYIP -s smtp.gmail.com -o tls=yes -xu username -xp password
echo $MYIP > myip.txt
fi
When I try to run it in the command line, it works perfectly. The problem starts when I include it in "crontab -e" like this: "* * * * * /home/ubuntu/myip.sh".
Then it does not work. Seem to be that the sendmail is not functioning properly.
When I do a: tail -f /var/log/syslog
Sep 18 21:48:02 gpuserver sendmail[18665]: r8J1m1gO018665: from=ubuntu, size=314, class=0, nrcpts=1, msgid=<201309190148.r8J1m1gO018665#gpuserver>, relay=ubuntu#localhost
Sep 18 21:48:02 gpuserver sendmail[18665]: r8J1m1gO018665: to=ubuntu, ctladdr=ubuntu (1000/1000), delay=00:00:01, xdelay=00:00:00, mailer=relay, pri=30314, relay=[127.0.0.1] [127.0.0.1], dsn=4.0.0, stat=Deferred: Connection refused by [127.0.0.1]
Any ideas?
When you run a script from the command line you are utilizing your current environment. Cron doesn't have that info ... So what you should do from the command line is:
env > me
Then edit the script and include ./me at the start of the script. That way your cron task will run with the same environment.
When a cron prints something to stdout or stderr, cron itself tries to send a report by e-mail. Since you probably don't have system-wide e-mail configured, this is probably where the error message in syslog is coming from.
To prevent cron from sending any mail, make sure your script and any commands it spawns don't output anything to stdout or stderr. An easy way to do this is to add "&>/dev/null" to your cron line.
You can also add 'MAILTO=""' at the beginning of your crontab.
This all documented in the man pages for cron/crontab (man -k cron).
Related
I am not in the root,
I entered the following commands in the crontab:
*/1 * * * * /home/ajain/testscript.sh
The file testscript.sh has the following commands:
#!/bin/bash
echo "The script begins now"
ping -c 2 live.com
echo The script has been run on `date` >> /home/ajain/testscript.log
echo "The script ends now"
exit
The crontab is not giving the results, however, the following command is giving the result in the testscript.log file correctly, displaying the ping date.
bash testscript.sh
Why is the crontab not working?
You can fix it in two different ways.
To provide full path to the script /home/ajain/testscript.sh. Here you don't even need to add bash because you have clearly mentioned in which shell your script should run i.e. first line of your script #!/bin/bash
Add this line before executing the script
set path=$path:/home/ajain/
testscript.sh # no need to use bash in front of it
Also providing execution permission to a script is not just enough. You need to check whether the user who is going to execute the script has permission to the location of the script or not. That means whether user can do a cd /home/ajain/ or not.
Hope this will help you.
remove >> /home/ajain/script.log, just add line to the top of file /home/ajain/testscript.sh:
#!/bin/bash
exec >> /home/ajain/script.log 2>&1
echo "The script begins now"
ping -c 2 live.com
echo "The script has been run on `date`"
echo "The script ends now"
exit
remove >> /home/ajain/script.log from crontab, just using:
*/1 * * * * /home/ajain/testscript.sh
You need do define script output.
Because of cron man page:
When executing commands, any output is mailed to the owner of the
crontab (or to the user named in the MAILTO environment variable in
the crontab, if such exists). The children copies of cron running
these processes have their name coerced to uppercase, as will be seen
in the syslog and ps output.
Fore everything else than echo The script has been run on 'date' >> /home/ajain/testscript.log you should check your/root's mail, or the syslog (eg. /var/log/syslog).
I could recommend make something like this:
*/1 * * * * /home/ajain/testscript.sh >> /home/ajain/script.log
#Edit
My crontab file on my user:
$crontab -l
# test
*/1 * * * * /home/3sky/tests/test.sh >> /home/3sky/tests/log.log
Script look like that:
#!/bin/bash
echo "The script begins now"
ping -c 2 live.com
echo The script has been run on `date`
echo "The script ends now"
exit
Permission on files:
test.sh - 0755/-rwxr-xr-x
log.log - 0644/-rw-r--r--
Output in log file:
$tail -20 log.log
2 packets transmitted, 0 received, 100% packet loss, time 10999ms
The script has been run on Thu Jun 21 12:18:12 CEST 2018
The script ends now
The script begins now
PING live.com (204.79.197.212) 56(84) bytes of data.
--- live.com ping statistics ---
2 packets transmitted, 0 received, 100% packet loss, time 10999ms
The script has been run on Thu Jun 21 12:19:12 CEST 2018
The script ends now
The script begins now
PING live.com (204.79.197.212) 56(84) bytes of data.
--- live.com ping statistics ---
2 packets transmitted, 0 received, 100% packet loss, time 10999ms
The script has been run on Thu Jun 21 12:20:12 CEST 2018
The script ends now
I am trying crontab but crontab for email is not working.However, I want that crontab runs a shell script and that shell script runs a python script.
One crontab I tried is
* * * * * echo " This is current date and time $(date)"
but this is not getting printed on screen. I don't understand what is wrong I am doing.
for sending the email form this command.
echo " This is a message " | mailx -s "Subject" mymail#email.com
you need to make sure port 25 is open on your system.
you can use the mailq command for check email in the queue on your system.
you can check local port is open or not from
telnet localhost 25
nc localhost 25
I have a bash script called test.sh which, for the sake of simplicity, prints one line to stdout and one line to stderr.
test.sh:
#!/bin/bash
echo "this is to stdout"
echo "this is to stderr" 1>&2
I want to run the script test.sh at 7:00 PM, but only if certain conditions are met. To this end, I have another bash script called schedule.sh, which checks some stuff and then submits the command to at to be run later.
I want the output of test.sh (both stdout and stderr) to be sent to me in an email. I use mailx to do this so I can get a nice subject name.
Furthermore, I want at to shut up. No output from at because it always sends me ugly emails (no subject line) if at produces any output.
schedule.sh:
#!/bin/bash
my_email="me#example.com" # Email is a variable
# Check some stuff, exit if certain conditions not met
echo "~/test.sh 2>&1 | mailx -s\"Cool title\" $my_email" | at 7:00 PM &> /dev/null
What's interesting is that when I run schedule.sh from cron (which runs the script with sh), it works perfectly. However, when I manually run schedule.sh from the terminal (NB: I'm using tcsh), at (not mailx) sends me an email saying
Ambiguous output redirect.
I'm not sure why the shell I run schedule.sh from makes a difference, when schedule.sh is a bash script.
Here is my thinking in looking at schedule.sh. Everything within the quotation marks "~/test.sh 2>&1 | mailx -s\"Cool title\" me#email.com" should be an argument to at, and at runs that argument as a command using sh. The redirection 2>&1 | is in the style of sh for this reason.
When I remove 2>&1 and only pipe the stdout of test.sh to mailx, it does work; however, I receive 2 emails: one with stdout from mailx and another from stderr from at.
What gives? How can I make this work regardless of the shell I'm calling it from?
Thanks.
edit:
uname -o says my OS is GNU/Linux
Here is uname -a if it helps:
Linux [hostname censored] 2.6.9-89.ELlargesmp #1 SMP Mon Jun 22 12:46:58 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux
When I check the at contents using at -c, here's what I see:
#!/bin/sh
# atrun uid=xxxxx gid=xxxxx
# mail username 0
# ...
SHELL=/bin/tcsh; export SHELL
# ...
${SHELL:-/bin/sh} << `(dd if=/dev/urandom count=200 bs=1 2>/dev/null|LC_ALL=C tr -d -c '[:alnum:]')`
~/test.sh 2>&1 | mailx -s"Cool title" me#example.com
I'm having a hard time understanding the second to last line... is this going to execute using $SHELL or /bin/sh?
The command executed via at is:
~/test.sh 2>&1 | mailx -s\"Cool title\" $my_email
The behavior of at command varies from one system to another. On Linux, the command is executed using /bin/sh. In fact, on my system (Linux Mint 14), it prints a warning message:
$ echo 'printenv > at.env' | at 19:24
warning: commands will be executed using /bin/sh
On Solaris, the command is executed by the shell specified by the current value of the $SHELL environment variable. Using an account where my default shell is /bin/tcsh on Solaris 9, I get:
% echo 'printenv > at.env' | at 19:25
commands will be executed using /bin/tcsh
job 1397874300.a at Fri Apr 18 19:25:00 2014
% echo 'printenv > at.env' | env SHELL=/bin/sh at 19:28
commands will be executed using /bin/sh
job 1397874480.a at Fri Apr 18 19:28:00 2014
Given that at's behavior is inconsistent (and frankly confusing), I suggest having it execute just a single command, with any I/O redirection being performed inside that command. That's the best way to ensure that the command will be executed correctly regardless of which shell is used to execute it.
For example (untested code follows):
echo '#!/bin/bash' > tmp.bash
echo "~/test.sh 2>&1 | mailx -s\"Cool title\" $my_email" >> tmp.bash
chmod +x tmp.bash
echo "./tmp.bash" | at 7:00 PM
Please consider following crontab (root):
SHELL=/bin/bash
...
...
0 */3 * * * /var/maintenance/raid.sh
And the bash script /var/maintenance/raid.sh:
#!/bin/bash
echo -n "Checking /dev/md0... "
if ! [ $(mdadm --detail /dev/md0 | grep -c "active sync") -eq 2 ]; then
mdadm --detail /dev/md0 | mail -s "Raid problem /dev/md0" "my#email.com";
echo "ERROR"
else
echo "ALL OK"
fi;
#-------------------------------------------------------
echo -n "Checking /dev/md1... "
...
And this is what happen when...
...executed from shell prompt (bash):
Mail with mdadm --detail /dev/md0 output is sent to my email (proper behaviour)
...executed by cron:
Blank mail is sent to my email (subject is there, but there is no message)
Why such difference and how to fix it?
As indicated in the comments, do use full paths on crontab scripts, because crontab does have different environment variables than the normal user (root in this case).
In your case, instead of mdadm, /sbin/mdadm makes it.
How to get the full path of a command? Using the command command -v:
$ command -v rm
/bin/rm
cron tasks run in a shell that is started without your login scripts being run, which set up paths, environment variables etc.
When building cron tasks, prefer things like absolute paths and explicit options etc
Before running your script as a cron job, you can test it with no environment variables using env -i
env -i /var/maintenance/raid.sh
I have a quesiton that puzzles me and I wonder if anyone has attempted to achieve the following:
Let's assume that this is the result of my 'last' command in a Linux environment:
root pts/1 192.168.1.10 Wed Feb 10 07:04 - 07:57 (00:52)
root pts/2 Tue Feb 9 22:00 - 00:13 (02:13)
How can I setup a particular action (say for example a modified MOTD or sending an email) if the the 'root' user has logged in from 192.168.1.10. Is there a way of capturing this information?
The second part of this question is that how can I make the above check a bit more robust - i.e. if I have the following:
mary pts/1 192.168.1.10 Wed Feb 10 07:04 - 07:57 (00:52)
bob pts/2 Tue Feb 9 22:00 - 00:13 (02:13)
Now I'd like to perform an action if the username is equal to 'mary' and the host is 192.168.1.10.
Any suggestions are welcomed.
Thank you in advance.
There's a special file /etc/ssh/sshrc where you can put some commands that will runs each time someone connect by ssh. I wrote that for you :
#!/bin/bash
mail=user#domain.tld
monitored_user=root
monitored_ip=x.x.x.x
hostname=$(hostname)
# add a welcome message:
printf >&2 "\nWelcome on $hostname $USER\n"
read -d " " ip <<< $SSH_CONNECTION
[[ $ip == $monitored_ip && $USER == $monitored_user ]] || exit 0
date=$(date "+%d.%m.%Y %Hh%M")
reverse=$(dig -x $ip +short)
mail -s "Connexion of $USER on $hostname" $mail <<EOF
IP: $ip
Reverse: $reverse
Date: $date
EOF
Put this script in a file, then put the full path of the script in /etc/ssh/sshrc
In man ssh :
/etc/ssh/sshrc :
Commands in this file are executed by ssh when the user
logs in, just before the user's shell (or command) is started. See the
sshd(8) manual page for more information.
Thanks for all your replies. Eventually I managed to find a solution which does work for the time being but it does have one flaw which I'll point out in a minute.
I have added the following to my /etc/bashrc file (or /etc/bash.bashrc whatever environment you're using):
HOST="192.168.0.1"
RHOST=`who am i | sed -n 's/.*(\([^) ]*\).*/\1/p; 1q'`
if [ "$RHOST" == "$HOST" ]; then
echo "SAY WHAT!"
#add further actions here if needed
fi
The flaw that I was talking about before may actually not be a flaw. If you're already SSH-ed into the system, and you want to SSH to a host which lives on the same IP, say ssh root#your-host who am i would then print 'your-host' but I think that's the way it should be.
Needless to say that the above sed statement can be modified so you can capture the username as well, and you can extend the if/else statement to suite your needs.
Thank you again for all your replies.
You can add something to /etc/profile or equivalent that does something depending on the value of $SSH_CLIENT.
It looks like you are using last because it reads /var/log/wtmp by default which is a record of logins. The who command also allows you to read the same file but with an interface more to your needs.
For example:
$ who --ips /var/log/wtmp | grep '^msw.*127.0.0.1'
msw pts/2 2012-10-07 15:52 127.0.0.1
msw pts/3 2012-10-07 15:55 127.0.0.1
where neither of those sessions were active, but rather historic and logged.
In ubuntu i put a script in
/etc/profile.d
and when someone(user ssh) log in, it send an email to my mail
#/etc/profile.d/run_on_loggin.sh
echo $(who i am) | mail -s 'SSH Login Notification' mymail#hotmail.com
I want to create a php file with smtp, to send email with my mail to me...
some times hotmail saved in spam...
if i have the php file i will run like this...
if i want to pass var to file php run like this...
excuse my english :3
note: i think this command run from user, be carefully if the user doen't has permission to use some command or send email.
One way would be to run a simple script periodically:
#!/bin/bash
users=$(last | sed -ne '/192\.168\.1\.10/ s/\([^ ]*\).*/\1/p')
for user in $users; do
sendmail "$user" < email.txt
done
This would pipe the last command into sed to extract a user list and save it into the variable $users. The sed command uses the -n flag so it only prints what we tell it to. First, we select lines that contain the specified IP, with the /192\.168\.1\.10/ "address". On those lines, we attempt to extract the characters before a space, and if we succeed we print the result.
Then, we can loop through the $users variable and act accordingly.
One way to call this repeatedly would be through cron, and a simpler way would be to do while true; do ./my_script.bash; sleep 60; done.